body {
    padding-top: 10px;
}
.all_bg {
    width: 800px;
    height: 600px;
    margin:0 auto;
}
#allCanvas {
    position: relative;
    width: 800px;
    height: 600px;
    margin: 0;
    #canvas1 {
        position: absolute;
        bottom: 0;
        left: 0;
        z-index: 1;
    }
    #canvas2 {
        position: absolute;
        bottom: 0;
        left: 0;
        z-index: 0;
    }
}
